1. Field of the Invention
The present invention relates to apparatus and method for developing photoresist on a substrate such as the semiconductor wafer, while supplying developer solution to the substrate which is being spin-rotated.
2. Description of the Related Art
In the photolithography process of making semiconductor devices, photoresist is coated on the semiconductor wafer, pattern-exposed and developed and developer solution is then cleaned and removed. In the developing process, developer solution is supplied on the wafer, which is being spin-rotated, through a nozzle and fully swelled on it due to a surface tension of liquid. In the conventional developing apparatus of the spray type, the nozzle is kept waiting at its home position when it is not used, and when it is to be used, developer solution deteriorated in it is dummy-dispensed at its or other specific position and then sprayed on the wafer through it. In this conventional apparatus, however, developer solution is caused to rush out through it just after the start of supplying, so that developer solution collides with the wafer surface with a big impact. The wafer surface is thus damaged and air bubbles thus caused in developer solution make the development uneven.
U.S. Pat. No. 5,374,312 discloses a developing apparatus in which the nozzle has a plurality of apertures at its solution supply portion and developer solution oozes out through these apertures. In this apparatus, however, developer solution comes from the developed surface of the wafer further onto an undersurface thereof, thereby tainting this undersurface, the spin chuck, the drive motor and others.